‘A great milestone’: Port tunnel-digger emerges from the depths

On the same spot on the MacArthur Causeway median where a giant tunnel boring machine began digging the tunnel to PortMiami on Nov. 11, 2011, the excavation ended Monday when the machine broke through the surface on its return from the port.

“This is a great milestone for us here today because basically the digging is done,” said Miami-Dade Mayor Carlos Gimenez, on hand when Harriet, the $45 million German-built boring machine, popped out of the ground at 7:59 a.m.

The under-the-bay tunnel is one of three major projects that form part of a comprehensive modernization of PortMiami aimed at attracting more cargo traffic once the widening of the Panama Canal is completed in 2015. The other improvements are dredging of the port’s cargo harbor and the upgrade of a rail line for cargo trains going to Jacksonville and a cargo distribution yard near Miami International Airport.

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It will take another year for the $1 billion tunnel project to be completed with paving of the two-lane highways inside the twin tubes of the tunnel, one going east from Watson Island to the port and one going west from the port to Watson Island.

It was at Watson Island where Harriet emerged from the ground, putting an end to about 18 months of excavation — roughly six months one way and six months the other, with the rest, turnaround time.

The purpose of the tunnel is to thin congestion on downtown streets by drawing to the tunnel thousands of cargo trucks that have to get to the seaport from area expressways including Interstate 95 and State Road 836.

Currently, the trucks get off the expressway at a ramp that leads them to Northeast Second Avenue or Biscayne Boulevard and then they meander through congested streets to get to the port via Port Boulevard.

Once the tunnel opens to traffic, possibly in May 2014, cargo trucks will be able to go directly from the expressways to the port. For example, a truck coming southbound on I-95 can turn eastbound onto I-395, which connects directly to the MacArthur Causeway and the entrance to the tunnel in front of Jungle Island.

Buses carrying cruise ship passengers also can use the tunnel for a direct expressway access to the port. The tunnel will be open to regular car traffic as well.

Besides building the tunnel roads, workers will be widening the MacArthur Causeway bridge and I-395 to accommodate the expected increased truck traffic.

The place where Harriet, as the tunnel boring machine is called, popped out was a solid wall painted with a cross-hairs in red. The wall was next to the entrance to the eastbound tunnel leg where boring began in 2011.

Tiny puffs of dust billowing out of the wall presaged Harriet’s arrival.

Slowly, the dust devils grew bigger. Then small chunks of rock broke off from the wall. Gradually, the chunks grew bigger, until huge slabs fell off the wall like a rock slide down a mountain. The machine’s giant circular cutting head then emerged behind a huge cloud of dust.

Hundreds of workers who had gathered at the site cheered and snapped pictures or took video with their phones and tablets.

Then came the speeches from Mayor Gimenez and the district chief in Miami for the Florida Department of Transportation, Gus Pego, thanking the workers for completing the excavation successfully.

“It’s a great day for Miami,” said Gimenez in his speech after the machine broke the surface. “Congratulations to everybody that’s worked on this project. I know we still have sometime to go, but this is a major milestone.”

Gimenez then recalled that despite initial doubts about the project, at one time even FDOT didn’t want to go forward, it will now be finished.

“A lot of people had doubts about this,” Gimenez said. “But we persevered and it’s going to be a great project for Miami-Dade County and it is going to make the port that much more accessible.”

Chris Hodgkins, vice president of Miami Access Tunnel, the multinational company that oversees construction of the project, said Harriet will be disassembled and its parts salvaged and recycled for future projects.